Tropical Cyclone Irene formed over the South Pacific Ocean west of Vanuatu on Wednesday morning. At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Irene was located at latitude 18.7°S and longitude 166.3°E which put it about 320 miles (520 km) west-southwest of Port Vila, Vanuatu. Irene was moving toward the east at 21 m.p.h. (33 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 990 mb.
An area of low pressure over the South Pacific Ocean strengthened rapidly on Wednesday morning and the Fiji Meteorological Service designated the system as Tropical Cyclone Irene. The inner end of a rainband wrapped around the western and southern side of Irene’s circulation. Other bands of thunderstorms were occurring in the eastern half of Tropical Cyclone Irene. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence that pumped mass away to the southeast of the tropical cyclone. Winds to tropical storm force extended out 115 miles (185 km) from the center of Irene.
Tropical Cyclone Irene will move through an environment favorable for intensification during the next 24 hours. Irene will move over over water where the Sea Surface Temperatures are near than 28˚C. An upper level trough east of Australia will produce northwesterly winds that will blow toward the top of Irene’s circulation. Those winds will cause vertical wind shear, but the wind shear will not be strong enough to prevent intensification. Tropical Cyclone Irene is likely to intensify during the next 24 hours. It could intensify rapidly during the next 12 hours. Irene could strengthen to the equivalent of a hurricane/typhoon.
The upper level trough east of Australia will steer Tropical Cyclone Irene quickly to the east-southeast during the next 24 hours. The center of Irene could pass near the southern islands of Vanuatu in 12 hours. The center of Tropical Cyclone Irene will be near Tanna and Aneityum in 12 hours. Irene could bring strong gusty winds and locally heavy rain to southern Vanuatu. Heavy rain could cause flash floods in some locations.